Author
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Hosfield, George |
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BEAVER, JAMES - UNIV OF PUERTO RICO |
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Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Proceedings Publication Acceptance Date: 3/1/2001 Publication Date: N/A Citation: N/A Interpretive Summary: Dry beans require a longer cooking time than many other foods to render the seeds palatable, inactivate antinutrients that breakdown with heat, and permit the digestion and assimilation of protein and carbohydrates. Cooking time of beans is very important in developing countries because beans are often cooked in pots on open wood fires that are not fuel efficient. The development of bean cultivars with faster cooking times than the cultivars currently grown might help conserve fuelwood. Moreover, a significant percentage of the annual U.S. bean crop is exported to developing nations who have expectations for beans with relatively short cooking times. We conducted an experiment on 37 dry bean genotypes to develop baseline data for variability in cooking time. The entries were representative of pinto, black, red-mottled, white, kidney, pink, and small-red market classes and have piqued the interested of growers in Caribbean and Central American countries. As a group, pinto beans were the fastest to cook (35.8 min) and the small-red market class genotypes were the slowest cooking (110.3 min). We determined that the cooking time of a sample and its water absorption after soaking was negatively associated (-0.84) indicating that fast-cooking beans imbibed more water than slow-cooking beans. Plant breeders can use the water absorption of a bean breeding line as an indirect, although, reliable prediction of cooking time. Since indirect selection for cooking time based on water absorption is rapid, there is no need to actually cook beans, which saves resources. Estimates indicate that a 24-minute reduction in cooking time of a bean variety could save as much as 165,000 tons of forest wood in a country with 1.1 million rural households. Technical Abstract: Cooking time is a major criterion for dry bean (Phaseolus vulgaris L.) utilization in countries of the Caribbean and Central America where this crop is a dietary staple and firewood is the main fuel source for cooking. We conducted an experiment to develop baseline data on genotypes of interest to growers in the Dominican Republic, Haiti, and several Central American countries. Thirty-seven cultivars and breeding lines were screened for their cooking time using a 25-well Mattson pindrop cooker. The genotypes were representative of pinto, black, red-mottle, white, kidney, pink, and small-red market classes. Beans were soaked and blanched and positioned into each of the 25 cylindrical holes of the cooker. A 105g rod with piercing tip was placed in contact with the surface of each bean. The apparatus with beans was submerged into boiling water. Cooking time was calculated as the elapsed time from initiation of the cooking until 19 of the 25 pins of the instrument had penetrated seeds. The experiment was replicated 4 times. Significant differences were detected among genotypes which individually ranged from 31.7 min to 154.6 min. As a group, pinto beans were the fastest cooking (35.8 min) and the small-red market class genotypes the slowest (110.3 min). A negative relationship (r=-0.84) was detected between cooking time and water absorption indicating that fast-cooking beans imbibed more water than slow cooking ones. Sufficient genetic variation exists among these genotypes to shorten cooking time through intermating and selection. The breeders can used the water absorption of a bean breeding line as an indirect, although, reliable prediction of cooking time. |
